(1) Field of the Invention
The present invention relates generally to markers for marking the external surface of a wire strand casing, and more particularly to an improved marker for simultaneously marking the entire perimeter surface of a cylindrical strand of material.
(2) Background Information
In wiring residential dwellings, several wire strands will terminate within an electrical box. The electrical box may be the location for an outlet, a switch, or other electrical device. Because residential dwellings are wired with conventional wire of the variety including a black casing, a white casing, and a bare ground wire, it often occurs at electrical boxes that several white wires terminate within a single box.
The national electrical code requires that the terminal end of any wire at an electrical box which is a "hot" wire, must be permanently marked with black ink along the terminal end of the casing. In this way, an electrician adding a particular electrical device, such as a switch or outlet, will know which wires are "hot" and which wires are "neutral".
In the prior art, the terminal ends of the wire are conventional marked with a black marker, requiring the flat tip of the marker to be run longitudinally along the length of the terminal end of the casing around all sides until the entire perimeter of the casing is permanently marked. While this task is not difficult, it is tedious and time consuming, when it is considered the number of boxes and terminal wire ends which commonly occur in a conventional residential dwelling.
If the wires are improperly marked, they are "red tagged" by an inspector, and require the electrician to return to the job site and complete the task of marking the terminal wires.
The same problem exists in other types of strand-like material, such as tubing or rope. For example, in the medical industry the use of intravenous (IV) solution delivery systems may require multiple IVs connected between a patient and multiple fluid sources.
One solution found in the prior art is the manufacture of a colored stripe directly in the product. This practice has been found both in the electrical industry and in the flexible tubing industry. However, the cost of manufacturing a product with a permanent stripe requires the modification of existing equipment, or the purchase of entirely new equipment, adding significantly to the cost of manufacture. Additionally, it would require an electrician to carry yet another type of wire along on every job. If multiple different strands are necessary, the user must maintain an extensive inventory of strands of a wide variety of different colored stripes.
U.S. Pat. No 5,954,443 to Bacon discloses an apparatus for marking a strand of material including a guide notch for directing the strand material against a marking nib. In one version of this invention, a notch is cut directly into the nib to guide the strand material along the marking nib. While this patent improves the reliability of marking the strand material, it still requires numerous passes along the length of the strand to mark the entire perimeter casing of the strand.
Similarly, the lubricant applicator disclosed in U.S. Pat. No. 2,930,061 discloses an arcuate shoe member with a curvature matching that of a cylindrical rod to be lubricated. Again, in order to lubricate the entire perimeter surface of the rod, either the rod must be rotated on its axis, and the lubricator moved the length of the rod a plurality of times to coat the entire length of the rod.